The imperative-and-declarative (IaD) construction in English (e.g. Study hard and you will pass the class) has two distinct readings: one that has the semantics of a conditional and additionally the meaning of an imperative, and one that has only the semantics of a conditional, with no imperative meaning. There are two general kinds of syntactic approaches in the literature for analyzing this construction: one that treats the two interpretations as underlyingly syntactically the same, and one that treats them as two distinct syntactic constructions. This short report presents the results of an acceptability-judgment experiment that was designed to inform the debate between the two kinds of approaches. The two types of IaDs were observed to behave differently with respect to two phenomena we evaluated, suggesting either that they should be treated as grammatically distinct, or that a theory that treats them as grammatically the same must give a pragmatic account of the differences. Furthermore, because the pattern of data that we observed was a statistical interaction between two factors—a pattern of data that is not detectable without quantitative measurements—the results provide compelling evidence for the need for quantitative evaluations of linguistic hypotheses.